Rater agreement of visual lameness assessment in horses during lungeing.

M. Hammarberg,T. Pfau,A. Egenvall,M. Rhodin

doi:10.1111/evj.12385

Abstract

SummaryReasons for performing studyLungeing is an important part of lameness examinations as the circular path may accentuate low‐grade lameness. Movement asymmetries related to the circular path, to compensatory movements and to pain make the lameness evaluation complex. Scientific studies have shown high inter‐rater variation when assessing lameness during straight line movement.ObjectivesThe aim was to estimate inter‐ and intra‐rater agreement of equine veterinarians evaluating lameness from videos of sound and lame horses during lungeing and to investigate the influence of veterinarians’ experience and the objective degree of movement asymmetry on rater agreement.Study designCross‐sectional observational study.MethodsVideo recordings and quantitative gait analysis with inertial sensors were performed in 23 riding horses of various breeds. The horses were examined at trot on a straight line and during lungeing on soft or hard surfaces in both directions. One video sequence was recorded per condition and the horses were classified as forelimb lame, hindlimb lame or sound from objective straight line symmetry measurements. Equine veterinarians (n = 86), including 43 with >5 years of orthopaedic experience, participated in a web‐based survey and were asked to identify the lamest limb on 60 videos, including 10 repeats. The agreements between (inter‐rater) and within (intra‐rater) veterinarians were analysed with κ statistics (Fleiss, Cohen).ResultsInter‐rater agreement κ was 0.31 (0.38/0.25 for experienced/less experienced) and higher for forelimb (0.33) than for hindlimb lameness (0.11) or soundness (0.08) evaluation. Median intra‐rater agreement κ was 0.57.ConclusionsInter‐rater agreement was poor for less experienced raters, and for all raters when evaluating hindlimb lameness. Since identification of the lame limb/limbs is a prerequisite for successful diagnosis, treatment and recovery, the high inter‐rater variation when evaluating lameness on the lunge is likely to influence the accuracy and repeatability of lameness examinations and, indirectly, the efficacy of treatment.

Highlights

Lameness is a frequent reason for decreased performance in horses and for veterinary intervention [1,2]
Studies have shown that vertical movement symmetry is systematically affected when trotting in a circle and asymmetry is most pronounced on the inner hindlimb [5,6]
Videos on induced forelimb lameness (n = 3) were evaluated correctly by 74% of the evaluators and for videos on hindlimb lameness (n = 5) by 37% of the raters. These results indicate that visual lameness assessment of horses trotting in a circle has poor agreement for less experienced equine veterinarians and moderately acceptable agreement for experienced orthopaedic equine practitioners

Summary

Introduction

Lameness is a frequent reason for decreased performance in horses and for veterinary intervention [1,2]. When evaluating lameness it is common practice to study the horse both on the straight and during lungeing, since it has been suggested that circling a horse in trot may enhance low grade lameness [3,4]. A number of factors may complicate the evaluation of lameness in horses during lungeing. Studies have shown that vertical movement symmetry is systematically affected when trotting in a circle and asymmetry is most pronounced on the inner hindlimb [5,6]. Circle size and speed will affect movement symmetry [7,8]. Compensatory lameness mechanisms are present during lungeing, especially for primary hindlimb lameness [6]

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